Duke Energy is required by North Carolina's Renewable Energy and Energy Efficiency Portfolio Standard (REPS) to have 12.5% of their electricity sales in North Carolina come from renewable energy and energy efficiency by 2021. There is also a solar component to the requirement which calls for 0.2% of their total sales to come from solar technologies by 2018. The utilities can comply with the law by purchasing renewable energy certificates (RECs) where one REC represents one megawatt-hour (MWh) of electricity generated by a renewable resource. Duke Energy is taking a variety of approaches to meet their portfolio requirements, including their standard purchase offer for RECs and an unsolicited bid process for RECs. Duke Energy is not required to purchase RECs in South Carolina or required to meet any renewable energy levels in South Carolina, but projects connected to Duke Energy's grid in South Carolina may qualify to supply RECs for Duke Energy's North Carolina requirements.

Duke Energy launched their REC-purchasing program in 2008. They have stated REC prices through 2027. For 2012 Duke is offering $5 per REC for general renewable energy RECs. Originally scheduled to increase over time, REC prices are now scheduled to remain at the current level through 2027. These prices are not part of a tariff, however, so Duke Energy may choose to change the rates or close the program altogether at any time. REC purchase agreements are not locked in at the rate offered in the year the agreement is signed. Instead, a REC provider who signs an agreement in 2012 will get paid at the 2012 rate for RECs generated in 2012, but then receive payments at the 2013 rate for RECs generated in 2013.

Facilities must be registered with the North Carolina Utilities Commission as a new certified renewable energy facility to participate in this program. The facility must also be interconnected with Duke Energy's electricity grid in the Carolinas. Systems that meet these requirements and are located in South Carolina are also eligible for this program. REC purchase agreement must be for at least 5 years and up to 15 years.